Scanning device having reduced scanning times and method related thereto

ABSTRACT

A scanning device includes a housing, a cold cathode fluorescent lamp (CCFL), and a light emitting diode (LED), a photosensor for detecting light that is emitted from the CCFL and the LED and then by way of a document, and a control circuit for controlling operations of the scanning device. The LED can be used to perform scans while the CCFL is heating.

BACKGROUND OF INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a scanning device, and moreparticularly, to a scanning device capable of reducing document scanningtimes.

[0003] 2. Description of the Prior Art

[0004] Scanning devices, such as fax machines, scanners, copiers, ormulti-function products with integrated print, scan and faxingfunctions, are popular electronics devices. These devices have ascanning device for obtaining a corresponding image from a document.

[0005] Please refer to FIG. 1, which is a block diagram of aconventional scanning device 10 according to the prior art. The scanningdevice 10 comprises a cover 11, a housing 12, a cold cathode fluorescentlamp (CCFL) 14, a photosensor 16 and a controller 18. The CCFL 14 isused for producing light. The photosensor 16, which can be aCharge-Coupled Device (CCD), is used for detecting light produced by theCCFL 14 that reflects off of a document 15. The controller 18 is usedfor controlling internal operations of the scanning device 10.

[0006] The basics of the scanning device 10 are described as follows.First, the desired document 15 is placed onto the scanning device 10 andthe cover 11 is closed, which prevents ambient light from influencingthe scanning process. Then, the CCFL 14 generates light to illuminatethe document 15, and the photosensor 16 detects the reflected light fromthe document 15. Since less light is capable of being reflected fromdark areas of the document 15, while more light is reflected from thebright areas of the document 15, the photosensor 16 is able to detectthe corresponding intensity variations of the reflected light. Finally,the controller 18 transforms the detected intensity patterns of thereflected light into digital data, and combines these digital data intoan image file.

[0007] Please refer to FIG. 2 in conjunction to FIG. 1. FIG. 2illustrates a relationship between intensity variations of the coldcathode fluorescent lamp versus time during a warm-up time period. Colorimage information is obtained by using the CCFL 14 of the scanningdevice 10 to scan a single time, and this is possible when asufficiently stable and bright light is produced by the CCFL 14. To doso, the CCFL 14 must reach a sufficiently high temperature to exciteenough ions to strike the fluorescent material disposed on the glasstube of the CCFL 14. In general, the period required to heat the CCFL 14to the appropriately high temperature is called the warm-up time period.A so-called warm-up time period(t₀˜t₁), with values of 45 to 90 seconds,is typically required. During the warm-up time period, a substantialluminance variation of the light provided by the CCFL 14 is exhibited.If the luminance variation is too great, corresponding errors for thereflected light detected by the photosensor 16 are created. From FIG. 2,the luminance variation of the light provided by the CCFL 14 in theperiod between t₀-t₁ is too great to permit color scans. As an example,during the period of t_(a)˜t_(b) as illustrated in FIG. 2, when usingthe CCFL 14 to scan the area 17 of the document 15 having a uniform graylevel, ideally the photosensor 16 should detect the same reflected lightluminance. However, because the luminance of the light provided by theCCFL 14 at the time t_(b) is larger than that at the time t_(a), thephotosensor 16 detects a different luminance for the same gray-levelarea 17, causing the controller 18 to read error-laden data, which leadsto incorrect image data. Hence, the CCFL 14 of the conventional scanningdevice 10 requires a relatively long warm-up time for generating asufficiently stable and bright light to ensure a high quality scan.

[0008] To reduce scanning times while maintaining high quality scans,the scanning device 10 may be provided more than one CCFL 14. In thisway, higher light intensities are available, but the warm-up time periodremains unchanged. This is a waste of time for the user.

SUMMARY OF INVENTION

[0009] It is therefore a primary objective of the claimed invention toprovide a scanning device for reducing scanning times and for providingscanning during the warm-up time period to solve the above-mentionedproblems.

[0010] Briefly summarized, the claimed invention provides a scanningdevice having a housing, a cold cathode fluorescent lamp (CCFL), and alight emitting diode (LED), both for emitting light, a photosensor fordetecting light that is emitted from the CCFL and the LED, and which isthen reflected from a document, and a control circuit for controllingoperations of the scanning device.

[0011] It is an advantage of the present invention that the LED may beused to perform scanning while the CCFL is being heated, therebyeliminating the need of the user to wait upon the warm-up time of theCCFL.

[0012] These and other objectives of the claimed invention will no doubtbecome obvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment, which isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF DRAWINGS

[0013]FIG. 1 is a block diagram of a conventional scanning deviceaccording to the prior art.

[0014]FIG. 2 illustrates a relationship between luminance variations ofa cold cathode fluorescent lamp depicted in FIG. 1 versus time.

[0015]FIG. 3 shows a block diagram of a scanning device according to thepresent invention.

[0016]FIG. 4 illustrates a relationship among luminance variations of afirst light source and a second light source depicted in FIG. 3 versustime.

[0017]FIG. 5 illustrates a block diagram of a computer system using ascanning device according to the present invention.

[0018]FIG. 6 is a flowchart for the block diagram of FIG. 5.

[0019]FIG. 7 is a perspective view of a multi-function product with ascanning device according to the present invention.

[0020]FIG. 8 is a block diagram of the multi-function product depictedin FIG. 7.

DETAILED DESCRIPTION

[0021] Please refer to FIG. 3, which shows a block diagram of a scanningdevice 20 according to the present invention. The scanning device 20comprises a housing 22, a scanning module 23, a photosensor 28, and acontroller 30. The scanning module 23 comprises a first light source 24and a second light source 26, both of which are used to produce light toilluminate a document 25. The photosensor 28 is used for detecting lightgenerated by both the first light source 24 and the second light source26 that is reflected from the document 25. The controller 30 is used forcontrolling operations of the scanning device 20. The warm-up timeperiod of the first light source 24 is longer than that of the secondlight source 26. The first light source 24 can be a cold cathodefluorescent lamp (CCFL). The second light source 26 can be a white-lightlight emitting diode (LED). The photosensor 28 can be a charge coupleddevice (CCD).

[0022] Please refer to FIG. 4, which illustrates a relationship betweenbrightness variations of the first light source 24 (curve A) and thesecond light source 26 (curve B) versus time according to the presentinvention. In the illustrative embodiment, the first light source 24 andthe second light source 26 are turned on simultaneously (time t₂ shownin FIG. 4). The second light source 26(curve B) is capable of quicklyemitting stable light, unlike the first light source 24 (curve A), whichneeds 45 to 90 seconds of warm-up time. Therefore, after enabling thesecond light source 26, the second light source 26 can generate light,however its luminance is lower than the light that the first lightsource 24 generates after being heated. During the warm-up time periodof the first light source 24, only the second light source 26 is used toscan the document. During this time, the first light source 24 isheated. In general, the warm-up time period of the first light source 24needs about 45-90 seconds. Suppose that the warm-up time period of thefirst light source 24 in this illustrative embodiment is 45 seconds (t₃as shown in FIG. 4), and so 45 seconds is set as a predetermined time.When the predetermined time of 45 seconds is reached, the controller 30simultaneously enables both the first light source 24 and the secondlight source 26, so that both light sources 24, 26 provide documentillumination. Then, the accumulated light luminance from the first lightsource 24 and the second light source 26 results in a more precise graylevel of the reflected light detected by the photosensor 28, and alowered exposure time. Finally, the controller 30 transforms thedifferent detected gray levels of light into corresponding digital data,and recombines these data to generate an image file readable by acomputer.

[0023] The scanning device 20 shown in FIG. 3 is a platform scanner.However, the scanning device20 also can be a flat bed scanner, a paperfed scanner, a copier, a Fax machine, or a multi-function product (MFP).Furthermore, both the second light source 26 and the first light source24 are installed within the scanning module 23.

[0024] Please refer to FIG. 5, which shows a block diagram of a computersystem 40 using the scanning device 20 according to the presentinvention. For simplicity, elements that have the same function as thatillustrated in FIG. 3 are provided the same item numbers used in FIG. 5.The scanning device20 can be a flat bed scanner or a document fedscanner. In the illustrative embodiment, the computer system 40comprises a display device 42 for displaying images, and an imageapplication 44, such as Photoshop published by Adobe, Photo Impact andPhoto Express published by Ulead, or OmniPage Limited Edition publishedby Caere. Such programs are used to initiate the operations of thescanning device 20. These applications have such functions as “preview”and “scan”. How the computer system 40 cooperates with the imageapplication 44 and the scanning device 20 is described as follow:

[0025] Please refer to FIG. 6 in conjunction to FIG. 5. FIG. 6 is aflowchart for the block diagram depicted in FIG. 5 according to thepresent invention.

[0026] Step 100:Start.

[0027] Step 102:Implement “preview” function.

[0028] Step 104: The scanning device 20 simultaneously enables thesecond light source 26 and the first light source 24. The first lightsource 24 begins heating.

[0029] Step 106:Perform preview scanning using the second light source26 and the heating first light source 24.

[0030] Step 108:Show the preview result on the display device 42 of thecomputer system 40.

[0031] Step 110: Implement the “scan” function.

[0032] Step 112: Scan the document using the second light source 26 andthe heated first light source 24.

[0033] Step 114:Show the scan result on the display device 42 of thecomputer system 40.

[0034] Step 116:End.

[0035] Regardless of whether it involves the entire document or only aportion of the document, the user is capable of performing a “preview”function provided by the image application 44 through an input interface46, such as a mouse or a keyboard, to verify the scanning scope of thedocument (step 102). Then, the computer system 40 sends a control signalto the controller 30 of the scanning device 20 to enable both the secondlight source 26 and the first light source 24 (step 104). Because thesecond light source 26 is capable of providing stable light immediately,the controller 30 can preview scan the document by using the secondlight source 26 in cooperation with the heating first light source 24(step 106). The preview scan result can be shown on the display device42 of the computer system 40 (step 108). The user may indicate whichregion of the document he or she desires, based on the preview scanresults. By this time, the first light source 24 has warmed up. The useris capable of performing a “scan” function provided by the imageapplication 44 through an input interface 46 to scan the desired regionof the document using both the second light source 26 and the firstlight source 24. Finally, the scan results can be shown on the displaydevice 42 of the computer system 40. From the above method, the heatedsecond light source 26 and the heating first light source 24 can usedfor performing preview scans, providing a copious warm-up time periodfor the first light source 24. In this way, the user can efficientlyutilize the image application software 44 cooperating with the secondlight source 26 and the first light source 24.

[0036] Please refer to FIG. 7 and FIG. 8. FIG. 7 is a perspective viewof the multi-function product 50 with the scanning device20 according tothe present invention. FIG. 8 is a block diagram of the multi-functionproduct 50 according to the present invention. The multi-functionproduct 50 comprises an operations pad 52, a scanning module 23, aphotosensor 28, and a controller 30. A first light source 24, which is aCCFL, and a second light source 26, which is a white light LED, areinstalled within the scanning module 23. The operations pad 52 has acontrol button 54 and a start button 56. When the start button 56 ispressed, the controller 30 turns on the first light source 24 and thesecond light source 26. When the control button 54 is pressed, thecontroller 30 only turns on the second light source 26. For simplicity,elements that have the same function as that illustrated in FIG. 3 areprovided the same item numbers used in FIG. 7.

[0037] Conventionally, the scanning module within the multi-functionproduct requires a warm-up time period so as to heat the CCFL to asufficient temperature. In other words, if the user only wants to copyor fax the document, he or she must wait a relatively long time due tothe warm-up time period of the CCFL. However, using the presentinvention multi-function product 50, if the user only desires tofacsimile or copy a document with a low scan quality, triggering thecontrol button 54 to only enable the second light source 26, which iscapable of generating stable light quickly, is available without waitingfor the additional warm-up time period of the first light source 24. Ifthe user desires to scan the document with a high quality scan,triggering the start button 56 to enable both the first light source 24and the second light source 26 is needed. In this way, the user avoidswaiting for the warm-up time period of the first light source 24.

[0038] In contrast to the prior art, the present invention scanningdevice is capable of performing a low quality scan by using the LEDduring the warm-up time period of the CCFL, and performing a highquality scan by using both the heated CCFL and the LED. This providesconvenience for the user, who can utilize the LED to perform a lowquality scan while the CCFL is being heated to avoid waiting for thewarm-up time period of the CCFL.

[0039] Those skilled in the art will readily observe that numerousmodifications and alterations of the device may be made while retainingthe teachings of the invention. Accordingly, the above disclosure shouldbe construed as limited only by the metes and bounds of the appendedclaims.

What is claimed is:
 1. A scanning device comprising: a first lightsource for generating light; a second light source for generating light;a photosensor for detecting light generated by the first light sourceand the second light source and then by way of a document; and acontroller for controlling the operation of the scanning device; whereina warm-up time period of the first light source is longer than a warm-uptime period of the second light source.
 2. The scanning device of claim1 wherein the first light source is a cold cathode fluorescent lamp(CCFL).
 3. The scanning device of claim 1 wherein the second lightsource is a white-light light emitting diode (LED).
 4. The scanningdevice of claim 1 wherein the photosensor is a charge coupled device(CCD).
 5. The scanning device of claim 1 wherein the scanning device isa flat bed scanner, a document fed scanner, a copier, a Fax machine, ora multi-function product (MFP).
 6. The scanning device of claim 1wherein the first light source and the second light source are installedwithin a scanning module of the scanning device.
 7. A method of scanninga document with a scanning device, the scanning device comprising afirst light source for generating light, a photosensor for detectinglight generated by the first light source and then by way of thedocument, and a controller for controlling operations of the scanningdevice, the method comprising: providing a second light source; enablingboth the first light source and the second light source after enablingthe scanning device; scanning the document using the second light sourcewhile the first light source is being heated; and scanning the documentusing both the first light source and the second light source to shortenthe exposure time of the photosensor when the first light source isheated; wherein a warm-up time period of the first light source islonger than a warm-up time period of the second light source.
 8. Themethod of claim 7 wherein the first light source is a cold cathodefluorescent lamp (CCFL).
 9. The method of claim 7 wherein the secondlight source a white-light light emitting diode (LED).
 10. The method ofclaim 7 wherein the photosensor is a charge coupled device (CCD). 11.The method of claim 7 wherein the scanning device is a flat bed scanneror a paper fed scanner.
 12. The method of claim 7 wherein the firstlight source and the second light source are installed within a scanningmodule of the scanning device.
 13. A multi-function product comprising:a scanning device comprising: a first light source for generating light;a second light source for generating light; a photosensor for detectinglight generated by the first light source and the second light sourceand then by way of a document; and a controller for controlling theoperations of the scanning device; and an operations pad connected tothe controller,the operations pad having a control button; wherein whenthe control button is triggered, the controller causes only the secondlight source to be enabled to scan the document; wherein a warm-up timeperiod of the first light source is longer than a warm-up time period ofthe second light source.
 14. The multi-function product of claim 13wherein the operations pad further comprises a start button, and whenthe start button is pressed the controller turns on the first lightsource and the second light source simultaneously and utilizes the firstlight source and the second light source to scan the document to shortenthe scanning time period.
 15. The multi-function product of claim 13wherein the first light source is a cold cathode fluorescent lamp(CCFL).
 16. The multi-function product of claim 13 wherein the secondlight source a white-light light emitting diode (LED).
 17. Themulti-function product of claim 13 wherein the photosensor is a chargecoupled device (CCD).